A scanning microscope which acquires an observed image of an observation target sample by scanning the sample with an excitation light, while stimulating the sample with a stimulation light, has been available (e.g. see Patent Document 1 and Patent Document 2).
In many cases when fluorescent observation of a sample is performed using a stimulation light and an excitation light which have a same wavelength in this kind of scanning microscope, a laser beam emitted from a same light source is split into the stimulation light and the excitation light using a beam splitting half-mirror. In this case, the stimulation light and the excitation light are scanned by different scanners and then combined by a beam combining half-mirror, and are irradiated onto the sample.
If fluorescence is generated from the sample by the irradiation of the excitation light, this fluorescence is received by a photodetector via the beam combining half-mirror and the beam splitting half-mirror, and an observation image of the sample is generated based on the electric signals generated as a result. The user can observe the observation surface of the sample by viewing the observation image acquired like this.
Patent Document 1: WO 2008/004336
Patent Document 2: Japanese Patent Application Laid-Open No. 2007-78773